Age-specific fertility rates are the number of live births (occurred or registered) during the calendar year, according to age of mother, per 1,000 of the female estimated resident population of the same age at 30 June. For calculating these rates, births to mothers under 15 years are included in the 15-19 years age group, and births to mothers aged 50 years and over are included in the 45-49 years age group. Pro rata adjustment is made in respect of births for which age of mother is not given.

Average annual rate of growth

The average annual growth rate, r, is calculated as a percentage using the formula:

where Po is the population at the start of the period, Pn is the population at the end of the period and n is the length of the period between Pn and Po in years.

Average household sizeAverage household size refers to the number of persons per household in private dwellings.

Birth

The delivery of a child, irrespective of the duration of pregnancy, who, after being born, breathes or shows any other evidence of life such as heartbeat.

Category of movement

Overseas arrivals and departures are classified according to length of stay (in Australia or overseas), recorded in months and days by travellers on passenger cards. There are three main categories of movement:

permanent movements

long-term movements (one year or more)

short-term movements (less than one year).

A significant number of travellers (i.e. overseas visitors to Australia on arrival and Australian residents going abroad) state exactly 12 months or one year as their intended period of stay. Many of them stay for less than that period and on their departure from, or return to, Australia are therefore classified as short-term. Accordingly, in an attempt to maintain consistency between arrivals and departures, movements of travellers who report their actual or intended period of stay as being one year exactly are randomly allocated to long-term or short-term in proportion to the number of movements of travellers who report their actual length of stay as up to one month more, or one month less, than one year.

Estimated resident population (ERP)

The official measure of the population of Australia is based on the concept of residence. It refers to all people, regardless of nationality or citizenship, who usually live in Australia, with the exception of foreign diplomatic personnel and their families. It includes usual residents who are overseas for less than 12 months. It excludes overseas visitors who are in Australia for less than 12 months.

Household

A household is a group of two or more related or unrelated people who usually reside in the same dwelling, who regard themselves as a household and who make common provision for food or other essentials for living; or a person living in a dwelling who makes provision for his or her own food and other essentials for living, without combining with any other person. Households include group households of unrelated persons, same-sex couple households, single-parent households as well as one-person households.

A household usually resides in a private dwelling (including caravans etc. in caravan parks). Persons usually resident in non-private dwellings, such as hotels, motels, boarding houses, jails and hospitals, are not included in household estimates.

This definition of a household is consistent with the definition used in the census. The number of households can be either based on count or estimated resident population.

Household estimate

Household estimate is a measure of the number of households of the usually resident population. It is based on the census count of households which is adjusted for missed households, households of overseas visitors, households of Australian residents where all members were temporarily overseas at the time of the census and households of Australian residents where all members were not home on census night and spent census night in a non-private dwelling in Australia.

Household population

The household population is the estimated resident population (ERP) that usually lives in private dwellings. It is the ERP less the population that usually lives in non-private dwellings.

Household size

Household size refers to the number of persons per household.

Infant mortality rate

The number of deaths of children under one year of age in a financial year per 1,000 live births in the same financial year.

Intercensal discrepancy

Intercensal discrepancy is the difference between two estimates at 30 June of a census year population, the first based on the latest census and the second arrived at by updating the 30 June estimate of the previous census date estimate with intercensal components of population change which take account of information available from the latest census. It is caused by errors in the start and/or finish population estimates and/or in estimates of births, deaths or migration in the intervening period which cannot be attributed to a particular source.

Intercensal error

Intercensal error is the difference between two estimates at 30 June of a census year population, the first based on the latest census and the second arrived at by updating the 30 June estimate of the previous census year with intercensal components of population change which do not take account of information available from the latest census.

Local Government Area (LGA)

Local Government Areas (LGA) are the spatial units which represent the geographical areas of incorporated local government councils and incorporated Community Government Councils (CGCs) where the CGC is of sufficient size and statistical significance. The various types of LGAs are cities (C), areas (A), rural cities (RC), towns (T), shires (S), district councils (DC) and municipalities (M). Further information concerning LGAs is contained in Australian Standard Geographical Classification (ASGC) (cat. no. 1216.0).

Long-term arrivals

Long-term arrivals comprise:

overseas visitors who intend to stay in Australia for 12 months or more (but not permanently)

Australian residents returning after an absence of 12 months or more overseas.

Long-term departures

Long-term departures comprise:

Australian residents who intend to stay abroad for 12 months or more (but not permanently)

overseas visitors departing who stayed 12 months or more in Australia.

Migration Adjustment

The ABS applies a number of adjustments to overseas arrivals and departures data in order to produce estimates of net overseas arrivals and departures (NOM). These mainly comprise adjustments designed to reflect differences between stated travel intentions and actual travel behaviour, but (in the case of revised NOM estimates) also include adjustments to transform numbers of overseas movements into numbers of travellers. Until recently, adjustments used by ABS to produce NOM estimates were collectively referred to as 'category jumping adjustments'. They are now referred to more simply as 'migration adjustments'.

Natural increase

Excess of births over deaths.

Net interstate migration

The difference between the number of persons who have changed their place of usual residence by moving into a given state or territory and the number who have changed their place of usual residence by moving out of that state or territory during a specified time period. This difference can be either positive or negative.

Net overseas migration

Net overseas migration is net permanent and long-term overseas migration plus an adjustment for the net effect of category jumping.

Net permanent and long-term movement

The difference between the number of permanent (settler) and long-term arrivals and the number of permanent and long-term departures. Short-term movements are excluded.

Overseas arrivals and departures (OAD)

Overseas arrivals and departures (OAD) refer to the arrival or departure of persons, through Australian airports (or sea ports), which have been recorded. Statistics on OAD relate to the number of movements of travellers rather than the number of travellers (i.e. the multiple movements of individual persons during a given reference period are all counted).

Permanent arrivals (settlers)

Permanent arrivals (settlers) comprise:

travellers who hold migrant visas (regardless of stated intended period of stay)

New Zealand citizens who indicate an intention to settle

those who are otherwise eligible to settle (e.g. overseas born children of Australian citizens).

This definition of settlers is used by the Department of Immigration and Multicultural and Indigenous Affairs (DIMIA). Prior to 1985 the definition of settlers used by the Australian Bureau of Statistics (ABS) was the stated intention of the traveller only. Numerically the effect of the change in definition is insignificant. The change was made to avoid the confusion caused by minor differences between data on settlers published separately by the ABS and the DIMIA.

Permanent departures

Permanent departures are Australian residents (including former settlers) who on departure state that they are departing permanently.

Population growth

For Australia, population growth is the sum of natural increase and net overseas migration. For states and territories, population growth also includes net interstate migration. After the census, intercensal population growth also includes an allowance for intercensal discrepancy.

Population projections

Population projections are not predictions or forecasts. They are an assessment of what would happen, in future years, to Australia's population given a set of assumptions about future trends in fertility, mortality and migration.

Short-term arrivals

Short-term arrivals comprise:

overseas visitors who intend to stay in Australia for less than 12 months

Australian residents returning after a stay of less than 12 months overseas.

Short-term departures

Short-term departures comprise:

Australian residents who intend to stay abroad for less than 12 months

overseas visitors departing after a stay of less than 12 months in Australia.

Standardised death rate

Standardised death rates enable the comparison of death rates between populations with different age structures by relating them to a standard population. The ABS standard populations relate to the years ending in 1 (e.g. 1991). The current standard population is all persons in the Australian population at June 2001. They are expressed per 1,000 or 100,000 persons. There are two methods of calculating standardised death rates:

The direct method - this is used when the populations under study are large and the age-specific death rates are reliable. It is the overall death rate that would have prevailed in the standard population if it had experienced at each age the death rates of the population under study.

The indirect method - this is used when the populations under study are small and the age-specific death rates are unreliable or not known. It is an adjustment to the crude death rate of the standard population to account for the variation between the actual number of deaths in the population under study and the number of deaths which would have occurred if the population under study had experienced the age-specific death rates of the standard population.

Wherever used, the definition adopted is indicated.

State or territory and Statistical Local Area (SLA) of usual residence

State or territory and Statistical Local Area (SLA) of usual residence refers to the state or territory and SLA of usual residence of:

the population (estimated resident population)

the mother (birth collection)

the deceased (death collection).

In the case of overseas movements, state or territory of usual residence refers to the state or territory regarded by the traveller as the one in which he/she lives or has lived. State or territory of intended residence is derived from the intended address given by settlers, and by Australian residents returning after a journey abroad. Particularly in the case of the former, this information does not necessarily relate to the state or territory in which the traveller will eventually establish a permanent residence.

Statistical District (S Dist)

Statistical Districts (S Dist) consist of selected, significant, predominantly urban areas in Australia which are not located within a Capital City Statistical Division (SD). S Dists enable comparable statistics to be produced about these selected urban areas. Further information concerning S Dists is contained in Australian Standard Geographical Classification (ASGC) (cat. no. 1216.0).

Statistical Division (SD)

Statistical Divisions (SD) consist of one or more Statistical Subdivisions (SSD). The divisions are designed to be relatively homogeneous regions characterised by identifiable social and economic units within the region, under the unifying influence of one or more major towns or cities. Further information concerning SDs is contained inAustralian Standard Geographical Classification (ASGC) (cat. no. 1216.0).

Statistical Local Area (SLA)

Statistical Local Areas (SLA) are, in most cases, identical with, or have been formed from a division of, whole Local Government Areas (LGA). In other cases, they represent unincorporated areas. In aggregate, SLAs cover the whole of a state or territory without gaps or overlaps. In some cases legal LGAs overlap statistical subdivision boundaries and therefore comprise two or three SLAs (Part A, Part B and, if necessary, Part C). Further information concerning SLAs is contained in Australian Standard Geographical Classification (ASGC) (cat. no. 1216.0).

Statistical Subdivision (SSD)

Statistical Subdivisions (SSD) are of intermediate size, between Statistical Local Areas (SLA) and Statistical Divisions (SD). In aggregate, they cover the whole of Australia without gaps or overlaps. They are defined as socially and economically homogeneous regions characterised by identifiable links between the inhabitants. In the non-urban areas an SSD is characterised by identifiable links between the economic units within the region, under the unifying influence of one or more major towns or cities. Further information concerning SSDs is contained inAustralian Standard Geographical Classification (ASGC) (cat. no. 1216.0).

Total fertility rate

The sum of age-specific fertility rates. It represents the number of children a woman would bear during her lifetime if she experienced current age-specific fertility rates at each age of her reproductive life.